- Liquefied gas as a fuel
- Organization of heating from a cylinder
- Which heat generator to use
- Pressure reducer
- Other elements
- Calculation of heating costs with liquefied gas
Gas heating is considered the most convenient and efficient. But if there is no possibility to connect to the gas pipeline, and the electric capacity is not enough? There is a way out – the boiler can be powered from cylinders. Let’s look at how to do it right, and what are the costs of heating a house with liquefied gas..
Liquefied gas as a fuel
LPG – liquefied petroleum gas – is produced from certain fractions of natural blue fuel or associated petroleum gases. The liquefaction process takes place at normal temperature conditions and a slight overpressure. At the same time, the finished product becomes significantly smaller in volume – about 250 times.
Any LPG is a mixture of propane and butane. Butane could be used on its own, but it does not evaporate well, so propane is added to it as a more active gas. Depending on the ratio of these gases in the composition, the physical and consumer properties of the mixture will change.
Important! In winter, when LPG volatility decreases due to low temperatures, it makes sense to use fuel with a higher propane content. And in the summer, when the gas increases in volume and there is a danger of depressurization, it is better to use mixtures with a predominance of butane.
According to GOST 20448-90, the classification of liquefied gas intended for municipal and domestic use is made:
- PT – if the mixture is more than? propane.
- BT – if there is more than a third of butane in the mixture.
- SPBT – with a butane content in the mixture from 25 to 60 percent.
Fuel intended for automotive engines can be labeled PA or PBA. They are also suitable for boilers, and the quality requirements for them, such as the remainder of liquid substances and various impurities, are usually higher..
In LPG cylinders it is partly in liquid, partly in gaseous form. As the mixture is consumed, the liquid gas evaporates and creates a working pressure in the cylinder. The efficiency of the installation is determined by how intensively the transition from the liquid to the gas phase occurs. A common problem is the “freezing” of liquefied gas in winter. At subzero temperatures, LPG evaporates poorly and the pressure in the system is not enough for the boiler burner to operate normally. There are solutions:
- Use a “winter” mixture (PT) – with an increased propane content, which will provide the necessary evaporation of the liquid phase and create pressure.
- Increase the number of cylinders used simultaneously. The more vessels are installed, the larger the area of the “mirror” of the gas in the liquid phase will be, the more it will evaporate.
- Apply a factory-made cylinder heating element.
In summer, the situation is reversed – evaporation is very intense, so the pressure can rise to critical, which is fraught with emergency situations. Solutions:
- In the warm season, switch to BT or SPBT.
- Fill cylinders incompletely.
- Exclude direct sunlight on the body of the container with gas.
- Apply automation and emergency valves to control pressure.
Organization of heating from a cylinder
Which heat generator to use
In this case, you can use any heating device designed for gas combustion. This can be a boiler for hot water heating or a heater / convector (including fireplaces and stoves with gas burners), which uses air transported through a system of channels as a heat carrier. Infrared gas emitters are increasingly used to heat non-residential premises from cylinders..
The performance of the heat generator is selected according to general rules, but it must be properly prepared for LPG. To do this, burners are changed to special ones, or the nozzles are replaced, which can be equipped with boilers. You also have to adjust the automation for minimum fuel consumption..
Important! Given the high cost of the energy carrier, it would be logical to purchase the most technologically advanced and economical heat generator, for example, of a condensing type..
This device is designed to convert and maintain a stable pressure. A reducer is necessary, since the pressure in the system is constantly changing, it depends on the type of LPG, temperature regime, number of vessels, gas residue, length of the fuel line. It is important to select a reducer according to the characteristics of the heat generator. Observe operating pressure and capacity.
Devices with indicators of 50, 42, 37, 32 mbar are on sale. Not so long ago, models appeared with the ability to adjust in the range from 20 to 60 mbar. If the pressure is low, the boiler will not work efficiently, or the burner will not start at all. If the pressure is too high, the boiler may break down and the burner will die out due to the “break-off” of the flame. The performance of the reducers used for cooking stoves is sometimes insufficient to power the boiler. They pass only 1 kg of gas per hour, while a 20 kW heat generator needs about 2-2.5 kg.
To power the heating system, it is necessary to use several containers at once, this is the only way to ensure the necessary pressure and less often you will have to refuel. As a rule, for a medium-sized cottage (100 m2) collect the battery in 6-8 vessels, which are located mainly in a straight line.
The containers are connected using combs or tees. In groups, they are connected to the heat generator through a common reducer. In this case, the multi-cylinder installation can be divided into two branches: operating and standby (automatically / manually turns on when the first group of vessels is empty).
Important! It is necessary to install cylinders outside the building in metal ventilated cabinets. The shorter the fuel line, the better. For safety reasons, the vessels should be filled no more than 85 percent of their volume (about 40 liters of the mixture are pumped into a 50-liter container – about 22 kg of LPG).
To assemble the system, many functional elements are used – mandatory and optional:
- high pressure hoses;
- combs and tees;
- manometers and pressure indicators;
- relief and check valves;
- high temperature and leakage safety cut-off devices;
- automatic and manual switches between groups of vessels;
- heating of the gearbox and cylinders;
- threaded / quick-release fittings.
Calculation of heating costs with liquefied gas
To generate a kilowatt of heat, the boiler will take a little more than 0.1 kilograms of liquefied gas per hour. For example, a house of 100 squares requires the installation of a heat generator with a capacity of about 10 kW. That is, up to 1–1.2 kg of LPG will be burned per hour, and up to 25 kg per day. But a modern technological boiler does not work all season at full capacity, a reduction factor of 0.5 is usually applied to the theoretical consumption. It turns out that in 7 months about 2625 kg of gas will be consumed: 25 x 30 x 7 = 5250 x 0.5 = 2625.
This type of heating is much more expensive than heating using mains gas, but if you do not have enough power for the heating system, then this method can be considered as an alternative. The only drawback of the system is the need to visit a gas station several times a month to refuel cylinders.